From: Al Viro <viro@ZenIV.linux.org.uk>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
Konstantin Khlebnikov <koct9i@gmail.com>,
linux-unionfs@vger.kernel.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC][PATH 4/4] ovl: relax lock_rename when moving files between work and upper dir
Date: Fri, 11 Nov 2016 15:40:34 +0000 [thread overview]
Message-ID: <20161111154034.GR19539@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CAOQ4uxibJf7BVSOeRdfcE7VtU2rkrii=Pu9OL0uZPavpudODeQ@mail.gmail.com>
On Fri, Nov 11, 2016 at 04:43:57PM +0200, Amir Goldstein wrote:
> > Surely, the copying of data itself is outside of that lock, isn't it?
>
> Mmmmmm, no it isn't, but I am going to make it right.
Well, if you really have the copyup itself done under lock_rename(), you
are looking at potentially copying gigabytes of data from r/o layer to
workdir under fs-wide lock. _That_ is really asking for contention from
hell, and for no good reason. Renames/whiteout creations/removals are
trivial noise compared to that. I'm somewhat surprised, TBH - I thought
the copyup itself is done outside of that thing. Are you sure it really
isn't?
next prev parent reply other threads:[~2016-11-11 15:40 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-10 22:44 [RFC][PATH 0/4] Reduce excessive use of lock_rename() in overlayfs Amir Goldstein
2016-11-10 22:44 ` [RFC][PATH 1/4] vfs: reinterpret sillyrename flag as delete lock Amir Goldstein
2016-11-10 22:44 ` [RFC][PATH 2/4] vfs: introduce delete trylock/unlock Amir Goldstein
2016-11-10 22:44 ` [RFC][PATH 3/4] ovl: delete lock upper dir and work dir Amir Goldstein
2016-11-10 22:44 ` [RFC][PATH 4/4] ovl: relax lock_rename when moving files between work and upper dir Amir Goldstein
2016-11-10 23:02 ` Al Viro
2016-11-10 23:05 ` Al Viro
2016-11-10 23:11 ` Amir Goldstein
2016-11-10 23:17 ` Al Viro
2016-11-10 23:33 ` Amir Goldstein
2016-11-10 23:54 ` Al Viro
2016-11-11 0:11 ` Amir Goldstein
2016-11-11 0:27 ` Al Viro
2016-11-11 14:43 ` Amir Goldstein
2016-11-11 15:40 ` Al Viro [this message]
2016-11-11 16:17 ` Amir Goldstein
2016-11-11 17:27 ` Al Viro
2016-11-11 17:44 ` Miklos Szeredi
2017-01-12 5:42 ` Amir Goldstein
2017-01-12 10:00 ` Miklos Szeredi
2017-01-12 18:18 ` Amir Goldstein
2016-11-11 18:07 ` Amir Goldstein
2016-11-12 19:45 ` Amir Goldstein
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